I'm usually a thorough vacation planner, starting months before the trip. However, our planned trip to Thailand had to be cancelled, and I spontaneously bought tickets to Cologne - we'll be there in three weeks and I'm pretty lost :-)
I'm coming with my 2 children - 15 and 10 for two weeks. We'd like a mostly outdoor vacation of walking, some cycling, nature parks, swimming, adventure parks, but also visits to small ancient cities. Ideally I hope to find 1-2 places to stay - with a lot of things to do and sights to see in a 100 km radius or so. Some trails nearby would be nice. We'll have a car.
Sorry for the rambling, but could somebody point me in a right directions - what regions should I research first? What places are interesting for kids? Should we stay for a couple of days in Cologne before going farther away or just come for a day trip from the countryside?